(1) Field of the Invention:
This invention relates to hot metal runners as used in the metal producing industry for delivering molten metal from a source to a remote point.
(2) Description of the Prior Art:
Runners for handling hot metal are disclosed in U.S. Pat. Nos. 4,039,172, 3,174,739 and 3,600,480.
The runner of U.S. Pat. No. 4,039,172 is a mass of refractory material coalesced under the influence of physical force with metal reinforcement members therein, the refractory material being one selected from those usable for conventional fire bricks such as clay. The metal reinforcement comprises flat bars and angles welded to one another to form a reinforcing skeleton in which the molding material is placed and subjected to physical force. A die is used to contain the reinforcing skeleton and the molding material during the compaction of the material into a coalesced mass of a uniform density throughout.
In the present invention the blast furnace runner unit is formed of layers of refractory material selected from those usable for conventional fire bricks such as clay and a suitable binder with each of the superimposed layers defining a cross sectionally trough-like configuration and of a different density with the first or lowermost layer being comparcted to the greatest density and the successive layers thereon comparcted to progressively lesser densities.
In the runner disclosed in U.S. Pat. No. 3,174,739, a metal shell contains a refractory lining which is formed of a permanent monolithic layer with a semi-permanent layer overlying the monolithic layer except at the discharge or nose end thereof. The semi-permanent layer is formed of magnesite or dolomite. The novelty in the patent relates to a nose formed on the discharge end of the runner of a refractory such as fire clay, crushed fire brick and black pitch with water to form a mortar which is applied as an end or nose over the monolithic layer and the semi-permanent layer of the runner. The disclosure therefore includes the metal shell, the two layers of appropriate material, which are not compacted, with the addition of the nose formed of the patching material including the black pitch.
This disclosure differs from the present invention in that there is no suggestion of the multiple layer mass formed of the refractory material with each of the layers being compacted to a different density. U.S. Pat. No. 3,600,480 relates to a process of repairing runners and incidentally discloses a runner in which the metal engaging uppermost surface termed an inside lining in the patent is formed of a composition of carbon and clay with a so-called outside lining made of silicon-carbide brick with the entire trough-like shape having a base of a still different material. The novelty in the patent relates to a patch applied to a worn away portion of the carbon and clay inside lining, the patch material comprising a mixture of particles of pitch and particles of carbon such as fine coke and pitch, which are noted in the patent as producing the highest density mentioned.
The structure of the runner disclosed is of uniform density as the same is not compacted by force.
In the present invention the hot metal runner discloses the successive layers of compacted materials of different densities with no carbon or pitch between any of the layers as such materials would adversely affect the ability of the layers of the hot metal runner to adhere together.
The prior art runners are therefore primarily of uniform density and with the exception of the disclosure of U.S. Pat. No. 4,039,172, are formed under thermal influence as heretofore customary in the art relating to the formation of refractory articles.